The long-term objectives of this program are directed toward the determination and quantification of fundamental data concerning the effects of hyperthermia given alone and in combination with ionizing radiation on selected critical normal tissues which are unavoidably exposed during therapeutic treatment of malignant tissue. The program will generate valuable information concerning the thermal tolerance of normal lung tissue and response ratios between normal and tumor tissue following whole or regional treatment of the lung using hyperthermia alone and in combination with ionizing radiation. Such data is essential for the effective understanding, utilization, and ultimate application of this modality in the clinical treatment of human patients. The specific aims of the program are (1) to continue to develop, utilize, and refine the techniques and thermography of systems we have developed for controlled localized microwave heating of mouse lung to temperatures of clinical intereat (41 degrees C - 45 degrees C); (2) to quantify thermal response separately and combined with ionizing radiation delivered to the whole lung or regionally and establish tolerance levels using lethality, functional assays (determination of temporal changes in respiration rate and in blood perfusion unsing Rb86 uptake) and pathologic analysis; (3) to determine the thermal sensitivity of artificial tumor metastases in the lung and the thermal enhancement of the radiation sensitivity of those tumors using treatments within acceptable limits for normal tissue damage. All studies will use inbred C3H/HeJ mice as a test model and will encompass the acute and chronic effects of microwave hyperthermia given alone and in combination with X-radiation on normal lung. Once the tolerance of this tissue is established, response ratios will be determined by treating appropriate tumors grown within the lung.